Page 183 - Advances in Renewable Energies and Power Technologies

156 CHAPTER 4 Performance of MPPT Techniques of Photovoltaic Systems

0-2 sec.
180 1
0-2 Sec
2-4 Sec
160 3
4-6 Sec
4-6 sec.
6-8 Sec
140
810 Sec
120 10-12 Sec 5
PV Power, W 100 FLC 8-10 sec. 4 5
MPSO
80
60 4 2
40 6
2
20
10-12 sec. 6-8 sec. 6
0
0 10 20 30 40 50 60
PV Voltage, V
FIGURE 4.43
The relation between the generated power along with terminal voltage and the MPPT
response for MPSO and FLC.

4. CONCLUSIONS
The generated power from the PV cells is changing with the operating voltage of the
PV cell for each radiation and temperature. There is an MPP at certain voltage of the
PV cells for each radiation and temperature. MPPT is used to track this point.
Tracking the MPP by using the FLC proves an exact tracking for the MPP even
in highly changing weather conditions. Fuzzy logic control system restrains any
overshooting in input or output systems and increases a considerable amount of
the energy captured. The FLC is implemented using FPGA.
Connecting many PV modules in series and parallel has been used to increase
voltage and current to be suitable for the load. Partial shading on some PV modules
will reduce the generated voltage of the PV system than the maximum power gener-
ated from each module separately. The shaded PV module will work as a load for
other PV module, which increases the hot spot on shaded PV module and it may
destroy these shaded PV modules. Bypass diodes should be connected across each
PV module to remedy the effect of partial shading on shaded PV modules. Connect-
ing several PV modules together will produce multiple peaks (one GP and multiple
LPs) on partial shading conditions. Maximum power point tracker techniques
(MPPT) have been used to follow the GP. Most of the MPPT techniques stick around
LPs. Modified particle swarm optimization (MPSO) technique has been used to
follow effectively the GP under all operating conditions with lower number of par-
ticles and iterations. This technique has been compared with FLC technique to